JP2014202469A - Heat pump unit and operation method of heat pump unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress foaming of a heating medium included in a lubricating oil and to prevent damage of a compressor when stopping the compressor.SOLUTION: A heat pump unit 200 includes: a circulation path 210 where a heating medium circulates; a compressor 230; a condenser 240; an expansion valve 260; an evaporator 220; and a control unit 280 for controlling a driving amount of the compressor and opening of the expansion valve, and controlling a circulation amount of the heating medium in the circulation path. When receiving an instruction to the effect that a compression operation of the heating medium by the compressor is stopped, the control unit reduces the opening of the expansion valve so that height of a liquid level of a lubricating oil accommodated in accommodation space does not become below a threshold value preset in the compressor, blocks the inflow of the heating medium into the compressor through the expansion valve by totally closing the expansion valve, and then, stops the compression operation of the heating medium by the compressor.

Description

  The present invention relates to a heat pump unit and a method for operating the heat pump unit.

  Conventionally, a compressor that adiabatically compresses and heats a heat medium circulating in a circulation path, a condenser that condenses the heat medium by cooling the heat medium heated by the compressor, and a heat medium condensed by the condenser 2. Description of the Related Art A heat pump unit is known that includes an expansion valve that cools by decompressing and cooling an evaporator, and an evaporator that vaporizes the heat medium by heating the heat medium cooled by the expansion valve. Such a heat pump unit is used in various fields such as a refrigerator, a freezer, an air conditioner, and a water heater.

  When stopping the operation of such a heat pump unit, for example, if the drive of the compressor is stopped without closing the expansion valve, the liquid heat medium remains in the evaporator. Then, when the operation of the heat pump unit is started next, the liquid heat medium remaining in the evaporator is directly introduced into the compressor, which may cause a malfunction.

  Therefore, when stopping the operation of the heat pump unit having an expansion valve that can be controlled on and off, a technique is disclosed in which the expansion valve is fully closed at one time before the drive of the compressor is stopped (for example, Patent Document 1). .

JP 2001-165511 A

  By the way, lubricating oil is supplied to the compression mechanism constituting the compressor, and in the heat pump unit, when the compressor adiabatically compresses the heat medium, the heat medium may be dissolved in the lubricating oil. In this case, when the expansion valve is fully closed at a time while the compressor is driven using the technique of Patent Document 1, the pressure in the compressor is rapidly reduced, and the heat medium dissolved in the lubricating oil is foamed. Resulting in.

  If it does so, the apparent viscosity of lubricating oil will fall, the oil film of lubricating oil will not fully be formed in a compression mechanism, abrasion of a compression mechanism may be accelerated | stimulated, and there exists a possibility that a compressor may be damaged.

  An object of the present invention is to provide a heat pump unit and a heat pump unit operating method capable of suppressing foaming of a heat medium contained in lubricating oil and preventing damage to the compressor when the compressor is stopped. It is.

  In order to solve the above problems, a heat pump unit according to the present invention has a circulation path through which a heat medium circulates, a compression mechanism, and an accommodation space in which lubricating oil supplied to the compression mechanism is accommodated, and circulates in the circulation path. A compressor that adiabatically compresses and heats the heat medium to be heated, a condenser that is provided downstream of the compressor in the circulation path and cools the heat medium heated by the compressor, and condenses the heat medium in the circulation path An expansion valve that is provided downstream of the condenser and cools the heat medium condensed by the condenser under reduced pressure, and a heat medium that is provided downstream of the expansion valve in the circulation path and is cooled by the expansion valve. An evaporator that vaporizes the heat medium, and a control unit that controls the drive amount of the compressor and the opening degree of the expansion valve to control the circulation amount of the heat medium in the circulation path. Compression of heat medium When the instruction to stop the operation is received, the opening of the expansion valve is reduced so that the level of the lubricating oil contained in the accommodation space does not become less than the threshold value preset in the compressor, After the expansion valve is fully closed and the flow of the heat medium into the compressor through the expansion valve is shut off, the compression operation of the heat medium by the compressor is stopped.

  In addition, the control unit reduces the opening of the expansion valve so that the rate of change of the opening of the expansion valve is maintained at a predetermined first value, so that the liquid of the lubricating oil stored in the storage space is reduced. The height of the surface may not be less than the threshold value.

  In addition, the control unit reduces the opening of the expansion valve so that the rate of decrease in the pressure of the storage space is maintained at a predetermined second value, so that the level of the lubricating oil stored in the storage space It is also possible to prevent the height of the lower than the threshold.

  In addition, the control unit, after fully closing the expansion valve, compresses the heat medium by the compressor until the pressure in the accommodation space becomes less than a pressure corresponding to a predetermined concentration of the heat medium contained in the lubricating oil. The operation may be maintained, and the compression of the heat medium by the compressor may be stopped when the pressure becomes less than a pressure corresponding to a predetermined concentration of the heat medium contained in the lubricating oil.

  In order to solve the above problems, an operation method of a heat pump unit of the present invention includes a circulation path through which a heat medium circulates, a compression mechanism, and an accommodation space that accommodates lubricating oil supplied to the compression mechanism, and is circulated. A compressor that adiabatically compresses and heats the heat medium circulating in the path, and a condenser that is provided downstream of the compressor in the circulation path and that condenses the heat medium by cooling the heat medium heated by the compressor, An expansion valve provided downstream of the condenser in the circulation path and cooled by decompressing and expanding the heat medium condensed by the condenser; and a heat medium provided downstream of the expansion valve in the circulation path and cooled by the expansion valve An operation method of a heat pump unit including an evaporator that vaporizes a heat medium by heating, and when receiving an instruction to stop the compression operation of the heat medium by the compressor, the heat pump unit is accommodated in the accommodation space. In order to prevent the liquid level of the lubricating oil from falling below a preset threshold value for the compressor, the opening of the expansion valve is reduced, the expansion valve is fully closed, and the compressor is connected to the compressor through the expansion valve. After blocking the inflow of the heat medium, the compression operation of the heat medium by the compressor is stopped.

  ADVANTAGE OF THE INVENTION According to this invention, when stopping a compressor, it becomes possible to suppress foaming of the heat medium contained in lubricating oil, and to prevent a compressor from being damaged.

It is a conceptual diagram for demonstrating a vacuum cleaning apparatus. It is a figure for demonstrating the structure of a compressor. It is a flowchart for demonstrating the flow of a process of the operating method of a heat pump unit.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiments are merely examples for facilitating the understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

  Conventionally, the heat pump unit is provided in various electric devices such as a refrigerator, a freezer, an air conditioner, and a water heater. In recent years, a vacuum cleaning apparatus for cleaning a workpiece under reduced pressure using the vapor of a hydrocarbon-based cleaning agent has been developed, and a heat pump unit is also used in the vacuum cleaning apparatus. Here, the workpiece refers to, for example, an industrial product, and the vacuum cleaning device cleans the workpiece and removes contaminants attached to the workpiece. In the present embodiment, a vacuum cleaning apparatus will be described as an example of an apparatus provided with a heat pump unit.

(Vacuum cleaning device 100)
FIG. 1 is a conceptual diagram for explaining the vacuum cleaning apparatus 100. In FIG. 1, the flow of the hydrocarbon-based cleaning agent is indicated by solid arrows, the flow of the heat medium is indicated by broken arrows, and the flow of signals is indicated by dashed-dotted arrows. As shown in FIG. 1, the vacuum cleaning apparatus 100 includes a vacuum container 104 in which a cleaning chamber 102 is provided. The vacuum container 104 has an opening (not shown), and the opening can be opened and closed by an opening / closing door (not shown). Therefore, when cleaning the workpiece W, the opening / closing door is opened, the workpiece W is loaded into the cleaning chamber 102 from the opening, the workpiece W is placed on the mounting portion 108, and the opening / closing door is closed to close the workpiece W. After cleaning, the opening / closing door is opened again, and the workpiece W is carried out from the opening.

  In the cleaning chamber 102, a shower unit 110 is provided. The steam chamber 150 is connected to the shower unit 110 through the steam supply pipe 114, the condensation chamber 120, the condensed cleaning agent supply pipe 122, the cleaning agent storage section 124, and the condensed cleaning agent supply pipe 126 in this order.

  The cleaning chamber 102 is provided with a steam supply unit 130. The steam supply unit 130 is communicated with the steam chamber 150 via the steam supply pipe 114.

  The steam chamber 150 includes a heater 152 and a condenser 240, and the hydrocarbon-based cleaning agent (solvent) is heated to, for example, about 80 to 140 ° C., preferably about 120 ° C., and the steam of the hydrocarbon-based cleaning agent. (Hereinafter simply referred to as “steam”). The steam generated in the steam chamber 150 is introduced into the condensing chamber 120 through the steam supply pipe 114 or supplied to the cleaning chamber 102 through the steam supply unit 130. The steam supplied by the steam supply unit 130 is condensed by adhering to the workpiece W. The heating mechanism by the condenser 240 will be described in detail later.

  The type of the hydrocarbon-based cleaning agent is not particularly limited, but it is desirable to use a third petroleum cleaning agent from the viewpoint of safety. For example, normal paraffinic, isoparaffinic, naphthenic, aromatic These hydrocarbon-based cleaning agents are listed. Specifically, Teclean N20, Clean Sol G, Daphne (registered trademark) solvent or the like called a cleaning solvent may be used as a cleaning agent for third petroleums.

  The condensing chamber 120 includes an evaporator 220, and the vapor introduced into the condensing chamber 120 is cooled by the evaporator 220 to be a liquid hydrocarbon-based cleaning agent (hereinafter simply referred to as “condensing cleaning agent”). Is condensed. The condensed cleaning agent is stored in the cleaning agent storage unit 124 through the condensed cleaning agent supply pipe 122 and then supplied to the cleaning chamber 102 through the condensed cleaning agent supply pipe 126 and the shower unit 110. It becomes. The cooling mechanism by the evaporator 220 will be described in detail later.

  The condensed cleaning agent supplied from the shower unit 110 and cleaning the workpiece W, and the condensed cleaning agent supplied from the vapor supply unit 130 and condensed by the workpiece W are passed through the used cleaning agent introduction pipe 128. Then, the steam is again introduced into the steam chamber 150 and is heated again by the heater 152 and the condenser 240 described above to become steam. As described above, the cleaning agent includes the steam chamber 150, the steam supply pipe 114, the condensation chamber 120, the condensed cleaning agent supply pipe 122, the cleaning agent storage section 124, the condensed cleaning agent supply pipe 126, the shower section 110, and the cleaning chamber 102. The used cleaning agent introduction pipe 128 is circulated.

  Further, a vacuum pump (not shown) is connected to the cleaning chamber 102 and the vapor chamber 150. This vacuum pump depressurizes the inside of the vacuum vessel 104 (cleaning chamber 102) to a predetermined pressure (for example, 6 kPa) by evacuation (initial vacuum) in a depressurization step before starting the cleaning of the workpiece W. It is. Further, a pipe (not shown) for opening the cleaning chamber 102 to the atmosphere is connected to the cleaning chamber 102. This piping is provided with an air release valve that shuts off the atmosphere and the cleaning chamber 102, and the cleaning chamber 102 is opened to the atmospheric pressure in the unloading process after the cleaning process and the drying process of the workpiece W are completed. It is to return to.

(Heat pump unit 200)
The heat pump unit 200 includes a circulation path 210 (indicated by 210a to 210f in FIG. 1), an evaporator 220, a compressor 230, a condenser 240, an intermediate heat exchanger 250, an expansion valve 260, and pressure measurement. A unit 270 and a control unit 280 are included. In the heat pump unit 200, the heat medium circulates in the circulation path 210 as shown by the broken arrows in FIG. 1, and the evaporator 220, the intermediate heat exchanger 250, the compressor 230, and the like provided in the circulation path 210, It is reintroduced into the evaporator 220 via the condenser 240, the intermediate heat exchanger 250, and the expansion valve 260. The type of the heat medium is not particularly limited, but is a fluorocarbon heat medium (for example, R-245fa (1) that is liquid at room temperature and atmospheric pressure and can use the latent heat of the heat medium in the evaporator 220. 1,1,3,3-pentafluoropropane)). Here, the normal temperature is, for example, 25 ° C.

  The evaporator 220 is disposed downstream of the expansion valve 260 in the circulation path 210 and performs heat exchange between the heat medium and the hydrocarbon-based cleaning agent steam introduced from the steam chamber 150 in the condensation chamber 120. The vapor is condensed (cooled) into a condensed cleaning agent, and the heat medium is heated and vaporized. Here, when heated by the evaporator 220, the heat medium becomes a gas (indicated by G in FIG. 1). The heat medium heated by the evaporator 220 is further heated by the intermediate heat exchanger 250. The heating mechanism by the intermediate heat exchanger 250 will be described in detail later.

  The compressor 230 is composed of, for example, a reciprocating compressor (reciprocating compressor), and has a compression mechanism and a storage space for storing lubricating oil supplied to the compression mechanism, and is heated by the intermediate heat exchanger 250. The heat medium is adiabatically compressed and further heated. A specific configuration of the compressor 230 will be described in detail later.

  The condenser 240 is disposed downstream of the compressor 230 in the circulation path 210, and performs heat exchange between the heat medium heated by the compressor 230 and the liquid hydrocarbon-based cleaning agent in the steam chamber 150. The hydrocarbon-based cleaning agent is heated to generate hydrocarbon-based cleaning agent vapor, and the heat medium is cooled and condensed. Here, by being cooled by the condenser 240, the heat medium is in a gas-liquid mixed state (indicated by G and L in FIG. 1).

  The intermediate heat exchanger 250 has a heat medium flowing through the circulation paths 210a and 210b (between the evaporator 220 and the compressor 230) and heat flowing through the circulation paths 210d and 210e (between the condenser 240 and the expansion valve 260). Heat exchange with the medium. The heat medium heated by the evaporator 220 and flowing through the circulation path 210a may not be completely vaporized but may be a gas-liquid mixed fluid. In this case, if the liquid heat medium is introduced into the compressor 230, the compressor 230 may be defective.

  Therefore, the configuration including the intermediate heat exchanger 250 heats the heat medium flowing through the circulation path 210a to a temperature higher than the saturation temperature, whereby the heat medium introduced into the compressor 230 (circulates through the circulation path 210b). It is possible to ensure that the heat medium is only gas. As a result, it is possible to avoid a situation in which a problem occurs in the compressor 230.

  The expansion valve 260 is a valve that causes a pressure drop of the fluid. The expansion valve 260 is provided downstream of the condenser 240 and further cools the heat medium condensed (cooled) by the condenser 240 by decompression. Here, by being cooled by the expansion valve 260, the heat medium becomes a liquid (indicated by L in FIG. 1). Then, the heat medium cooled in the expansion valve 260 is again introduced into the evaporator 220 through the circulation path 210f.

  The pressure measurement unit 270 measures the pressure of the gas part in the storage space described later in the compressor 230.

  The control unit 280 is composed of a semiconductor integrated circuit including a CPU (Central Processing Unit), reads a program and parameters for operating the CPU itself from the ROM, and cooperates with the RAM as a work area and other electronic circuits. The entire heat pump unit 200 is managed and controlled. In the present embodiment, the control unit 280 controls the driving amount of the compressor 230 and the opening degree of the expansion valve 260 based on the pressure measured by the pressure measuring unit 270, thereby controlling the circulation amount of the heat medium in the circulation path 210. To do.

  By the way, as described above, the heat medium may be dissolved in the lubricant contained in the compressor 230. Hereinafter, the mechanism in which the heat medium is dissolved in the lubricating oil accommodated in the compressor 230 will be described with reference to FIG.

  FIG. 2 is a diagram for explaining the configuration of the compressor 230. In FIG. 2, the flow of the heat medium is indicated by solid arrows, the flow of the lubricating oil is indicated by white arrows, and the lubricating oil is indicated by gray filling. As shown in FIG. 2, the piston (compression mechanism) 232 of the compressor 230 is connected to a drive shaft (compression mechanism) 234, and when the drive shaft 234 is rotationally driven by a motor (not shown), the piston 232 is The reciprocating motion is performed with respect to the compression chamber 236. When the piston 232 is positioned near the bottom dead center, the heat medium is introduced from the circulation path 210b to the compression chamber 236 via the inlet 238a of the compressor 230. The heat medium introduced into the compression chamber 236 is compressed by the compression operation of the piston 232, and then sent out from the outlet 238b to the circulation path 210c when the piston 232 is positioned near the top dead center.

  As shown in FIG. 2, a storage space R for storing lubricating oil (for example, POE (polyol ester)) is formed inside the compressor 230, and the lubricating oil stored in the storage space R is The oil is supplied to the oil passage 312 of the drive shaft 234 by the lubricating oil pump 310. The lubricating oil supplied to the oil passage 312 passes through an oil passage (not shown) of the piston 232 and is supplied to the outer peripheral surface of the piston 232. Further, the lubricating oil accommodated in the accommodating space R is supplied to the connecting portion of the piston 232 and the drive shaft 234, the outer peripheral surface of the piston 232, and the inner peripheral surface of the compression chamber 236 by the spreading unit 320. As described above, the lubricating oil is supplied to the outer peripheral surface of the piston 232 and the inner peripheral surface of the compression chamber 236, thereby reducing the friction coefficient between the piston 232 and the compression chamber 236 and reducing the wear of the piston 232 and the compression chamber 236. Reduced.

  As described above, since the heat medium is introduced into the compression chamber 236 in the heat pump unit 200 and the lubricating oil is supplied to the inner peripheral surface of the compression chamber 236, the heat medium is supplied to the lubricating oil in the compression chamber 236. May dissolve. Then, the lubricating oil circulates in a state where the heat medium is dissolved, that is, the compression operation is maintained in a state where the heat medium is dissolved in the lubricating oil.

  As described above, when stopping the operation of the heat pump unit 200, if the driving of the compressor 230 is stopped without closing the expansion valve 260, a liquid heat medium remains in the evaporator 220, and then the heat pump unit 200 When the operation is started, the liquid heat medium remaining in the evaporator 220 is introduced into the compressor 230 as it is, which may cause a malfunction of the compressor 230. Therefore, when the heat pump unit 200 is stopped, in order to avoid the liquid heat medium remaining in the evaporator 220, the compressor 230 is driven, and the expansion valve 260 is fully closed at a time when the compressor 230 is driven. The pressure in the housing space R of 230 may drop rapidly, and the heat medium dissolved in the lubricating oil of the compressor 230 may foam and damage the compressor 230. For example, bubbles of the heat medium may reach the compression chamber 236.

  In particular, the heat medium used in the heat pump unit 200 of the vacuum cleaning apparatus 100 is lubricated more than the heat medium used in the heat pump unit of a refrigerator, a freezer, an air conditioner, a water heater, etc. (hereinafter referred to as “home appliance device”). It is easy to dissolve in oil. Specifically, in order to generate the vapor of the hydrocarbon-based cleaning agent in the vacuum cleaning apparatus 100, it is necessary to heat the hydrocarbon-based cleaning agent to a high temperature such as about 80 ° C to 140 ° C. Therefore, the boiling point of the heat medium used for the heat pump unit 200 of the vacuum cleaning device 100 is higher than that of the heat medium used for the heat pump unit of the home appliance. For example, the temperature of the compressor inlet of the heat medium used in the heat pump unit of the home appliance is about 90 ° C., and the compressor outlet temperature is about 110 ° C. On the other hand, the temperature of the inlet 238a (heat medium passing through the circulation path 210b) of the heat medium compressor 230 used in the heat pump unit 200 of the vacuum cleaning apparatus 100 is about 100 ° C to 110 ° C. The temperature of the outlet 238b (heat medium passing through the circulation path 210c) is about 140 ° C.

  Such a heat medium having a relatively high boiling point has a higher solubility in the lubricating oil of the compressor 230 constituting the heat pump unit 200 than a heat medium having a relatively low boiling point. More specifically, the heat medium used in the heat pump unit of the home appliance is only about a few percent dissolved in the lubricating oil of the compressor, but the heat medium used in the heat pump unit 200 of the vacuum cleaning device 100 is compressed. About 20% may be dissolved in the lubricating oil of the machine 230. Therefore, in the compressor 230 of the heat pump unit 200 of the vacuum cleaning device 100, foaming of the heat medium becomes more conspicuous than the compressor of the heat pump unit of the household electrical appliance, and the compressor 230 is damaged due to a decrease in the liquid level LH of the lubricating oil. Is likely.

  Therefore, when the compressor 230 is stopped, the control unit 280 adjusts the opening degree of the expansion valve 260 to suppress foaming of the heat medium in the accommodation space R of the compressor 230. Hereinafter, stop control of the compressor 230 by the control unit 280 will be described.

(Stop control of compressor 230)
When the control unit 280 receives an instruction to stop the heat pump unit 200, that is, an instruction to stop the compression operation of the heat medium by the compressor 230, the control unit 280 receives the lubricant oil stored in the storage space R of the compressor 230. The opening degree of the expansion valve 260 is reduced so that the height of the liquid level LH does not become less than a threshold value preset in the compressor 230. Here, the threshold value set in advance in the compressor 230 is the level of the lubricating oil required for lubrication between the connecting portion of the piston 232 and the drive shaft 234 and between the outer peripheral surface of the piston 232 and the inner peripheral surface of the compression chamber 236. Is the lower limit of the height.

  The controller 280 controls the opening degree of the expansion valve 260 so that the height of the liquid level LH of the lubricating oil accommodated in the accommodating space R of the compressor 230 does not become less than a threshold value preset in the compressor 230. In the case of reducing the size, for example, the following four means can be mentioned.

(Opening adjustment 1 of the expansion valve 260 by the controller 280)
The control unit 280 reduces the opening degree of the expansion valve 260 so that the change rate of the opening degree of the expansion valve 260 is maintained at a predetermined first value, so that the lubrication accommodated in the accommodation space R is maintained. The height of the oil level LH should not be less than the threshold value. Here, when the opening when the expansion valve 260 is fully open is 100%, the first value is, for example, 3% / min.

(Opening adjustment 2 of the expansion valve 260 by the control unit 280)
The control unit 280 reduces the opening of the expansion valve 260 so that the pressure decrease rate of the storage space R measured by the pressure measurement unit 270 is maintained at a predetermined second value. The height of the liquid level LH of the lubricating oil accommodated in the space R is prevented from becoming less than the threshold value. Here, the second value is, for example, a rate of decrease of (10% of the pressure during normal operation of the compressor 230) / min or less. Therefore, when the pressure during normal operation of the compressor 230 is, for example, 500 kPa, the second value is 50 kPa / min.

(Opening adjustment 3 of the expansion valve 260 by the control unit 280)
The compressor 230 is provided with a liquid level gauge, and the control unit 280 is configured such that the height of the liquid level LH of the lubricating oil stored in the storage space R of the compressor 230 is less than a threshold set in the compressor 230 in advance. In order to prevent this, the opening of the expansion valve 260 is reduced. For the liquid level meter, for example, an existing technology such as an optical sensor or an image processing apparatus can be used.

(Opening adjustment 4 of the expansion valve 260 by the control unit 280)
The compressor 230 is provided with a device for measuring the amount of bubbles, and the control unit 280 opens the opening of the expansion valve 260 so that the bubbles generated in the storage space R of the compressor 230 do not exceed a predetermined amount. Make it smaller. Here, the predetermined amount is the upper limit value of the amount of bubbles that can be lubricated between the connecting portion of the piston 232 and the drive shaft 234 and between the outer peripheral surface of the piston 232 and the inner peripheral surface of the compression chamber 236. . As an apparatus for measuring the amount of bubbles, for example, an existing technique such as a void ratio meter, an optical sensor, an image processing apparatus, or the like can be used.

  Based on the values described in the opening adjustments 1 to 4 described above, by reducing the opening of the expansion valve 260, the height of the liquid level LH of the lubricating oil housed in the housing space R of the compressor 230 is reduced. It is possible to prevent the compressor 230 from becoming less than a preset threshold value.

  Therefore, before stopping the driving of the compressor 230, the pressure in the accommodation space R can be gradually reduced, and the foaming of the heat medium dissolved in the lubricating oil can be suppressed. Therefore, a situation in which the apparent viscosity of the lubricating oil is reduced can be avoided, and a sufficient oil film of the lubricating oil can be formed on the sliding members such as the piston 232, the drive shaft 234, and the compression chamber 236. As a result, it is possible to avoid a situation in which the sliding member is worn and the compressor 230 is damaged.

  Then, the control unit 280 fully closes the expansion valve 260 to block the flow of the heat medium into the compressor 230 through the expansion valve 260, and then the pressure in the accommodation space R measured by the pressure measurement unit 270 is the lubricating oil. The compression operation of the heat medium by the compressor 230 is maintained until the pressure becomes less than a pressure corresponding to a predetermined concentration of the heat medium contained therein (hereinafter referred to as “equivalent pressure”). Here, the equivalent pressure is, for example, 40 kPaG.

  Thus, since the control part 280 stops the drive of the compressor 230 after fully closing the expansion valve 260, the situation where the liquid heat medium remains in the evaporator 220 can be prevented. Thereby, when the control part 280 starts the operation | movement of the heat pump unit 200 next, since the heat medium of a liquid state is no longer introduced into the compressor 230, damage to the compressor 230 can be prevented.

  In addition, after the expansion valve 260 is fully closed, the control unit 280 maintains the compression operation of the heat medium by the compressor 230 until the pressure in the accommodation space R measured by the pressure measurement unit 270 becomes less than the equivalent pressure. The heat medium dissolved in the lubricating oil can be vaporized. Therefore, the heat medium can be removed from the lubricating oil, and the foaming of the heat medium in the lubricating oil, that is, the decrease in the liquid level LH of the lubricating oil is suppressed when the operation of the heat pump unit 200 is started next. Is possible.

(Operation method of heat pump unit 200)
Subsequently, an operation method of the heat pump unit 200, in particular, a stop method will be described. FIG. 3 is a flowchart for explaining the processing flow of the operation method of the heat pump unit 200. The stop control of the heat pump unit 200 is a process performed when the heat pump unit 200 is in operation.

  When control unit 280 receives an instruction to stop the compression operation of the heat medium by compressor 230 in response to an operation input by the operator (YES in step S410), control unit 280 is accommodated in accommodation space R of compressor 230. The opening degree of the expansion valve 260 is decreased so that the height of the liquid level LH of the lubricating oil does not become less than the threshold value A preset in the compressor 230 (step S412).

  Then, the control unit 280 determines whether or not the expansion valve 260 is fully closed (step S414). If the expansion valve 260 is not fully closed (NO in step S414), the process of step S412 is continued.

  On the other hand, when expansion valve 260 is fully closed (YES in step S414), control unit 280 determines whether or not the pressure in housing space R of compressor 230 measured by pressure measurement unit 270 is less than the equivalent pressure. Is determined (step S416). When the pressure in the accommodation space R is not less than the equivalent pressure (NO in step S416), the control unit 280 maintains the drive of the compressor 230, and when the pressure in the accommodation space R becomes less than the equivalent pressure (YES in step S416). The driving of the compressor 230 is stopped (step S418).

  As described above, according to the heat pump unit 200 and the operation method of the heat pump unit 200 according to the present embodiment, foaming of the heat medium contained in the lubricating oil can be suppressed when the compressor 230 is stopped. It becomes possible to prevent the compressor 230 from being damaged.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Is done.

  For example, in the above-described embodiment, the heat pump unit 200 constituting the vacuum cleaning apparatus 100 has been described as an example, but the apparatus on which the heat pump unit 200 is mounted is not limited. For example, even if the heat pump unit is installed in various electric devices such as a refrigerator, a freezer, an air conditioner, and a water heater, since the heat medium is dissolved in the lubricating oil of the compressor, the heat pump unit 200 and the heat pump unit 200 of the present invention. The driving method can be applied.

  Further, in the above-described embodiment, the control unit 280 fully closes the expansion valve 260 and then the heat medium generated by the compressor 230 until the pressure in the accommodation space R measured by the pressure measurement unit 270 becomes less than the equivalent pressure. The configuration for maintaining the compression operation has been described. However, the compression operation of the heat medium by the compressor 230 may be maintained for a time when the pressure is less than the corresponding pressure after the expansion valve 260 is fully closed.

  In the above-described embodiment, the configuration in which the heat pump unit 200 includes the intermediate heat exchanger 250 has been described. However, even if the intermediate heat exchanger 250 is not provided, the heat pump unit 200 is included in the lubricating oil when the compressor 230 is stopped. Foaming of the heat medium can be suppressed and damage to the compressor 230 can be prevented.

  Further, in the above-described embodiment, the vacuum cleaning apparatus 100 in which the cleaning with the condensed cleaning agent supplied from the shower unit 110 and the cleaning with the vapor supplied from the vapor supply unit 130 are performed in the cleaning chamber 102 has been described. However, for example, an immersion chamber may be provided in the vacuum container 104 below the cleaning chamber 102, and the workpiece W may be cleaned by immersing the workpiece W in the immersion chamber.

  Specifically, in the immersion chamber, an amount of hydrocarbon-based cleaning agent (liquid) that can completely immerse the workpiece W is stored, and a heater for heating the hydrocarbon-based cleaning agent is provided. ing. Further, an intermediate door is provided between the cleaning chamber 102 and the immersion chamber, and the intermediate door allows the cleaning chamber 102 and the immersion chamber to communicate with each other or the communication to be interrupted. . Note that the hydrocarbon-based cleaning agent stored in the immersion chamber includes the condensed cleaning agent supplied from the shower unit 110 and the condensed cleaning agent supplied from the cleaning agent storage unit 124 via the condensed cleaning agent supply pipe 126. Either one or both. Further, in this case, an elevating device is provided in the placement unit 108, and the placement unit 108 is configured to be movable in the vertical direction. Therefore, the workpiece W is moved from the cleaning chamber 102 to the immersion chamber by driving the lifting device in a state where the intermediate door is opened and the cleaning chamber 102 and the immersion chamber are communicated, or the workpiece W is moved to the immersion chamber. The workpiece W is cleaned by moving it to the cleaning chamber 102.

  Each step of the operation method of the heat pump unit of the present specification does not necessarily have to be processed in time series in the order described as the flowchart, and may include processing in parallel or by a subroutine.

  The present invention can be used for a heat pump unit and a method for operating the heat pump unit.

200 heat pump unit 210 circulation path 220 evaporator 230 compressor 232 piston (compression mechanism)
234 Drive shaft (compression mechanism)
240 Condenser 260 Expansion Valve 270 Pressure Measurement Unit 280 Control Unit

Claims (5)

A circulation path through which the heat medium circulates;
A compressor having a compression mechanism and a storage space for storing lubricating oil supplied to the compression mechanism, and adiabatically compressing and heating the heat medium circulating in the circulation path;
A condenser that is provided downstream of the compressor in the circulation path and that condenses the heat medium by cooling the heat medium heated by the compressor;
An expansion valve that is provided downstream of the condenser in the circulation path and cools the heat medium condensed by the condenser by decompressing and expanding;
An evaporator provided downstream of the expansion valve in the circulation path and evaporating the heat medium by heating the heat medium cooled by the expansion valve;
A control unit for controlling the amount of the heat medium in the circulation path by controlling the driving amount of the compressor and the opening of the expansion valve;
With
When the control unit receives an instruction to stop the compression operation of the heat medium by the compressor,
The opening of the expansion valve is reduced so that the level of the lubricating oil stored in the storage space does not become less than a threshold value preset in the compressor,
A heat pump unit characterized in that after the expansion valve is fully closed and the flow of the heat medium into the compressor through the expansion valve is shut off, the compression operation of the heat medium by the compressor is stopped.   The control unit reduces the opening degree of the expansion valve so that the change rate of the opening degree of the expansion valve is maintained at a predetermined first value, so that the lubricating oil contained in the accommodation space is maintained. 2. The heat pump unit according to claim 1, wherein the liquid level of the liquid is not less than the threshold value.   The control unit reduces the opening of the expansion valve so that the rate of decrease in the pressure of the storage space is maintained at a predetermined second value, so that the lubricating oil stored in the storage space is reduced. The heat pump unit according to claim 1, wherein the height of the liquid level does not become less than the threshold value. The controller, after fully closing the expansion valve,
Maintaining the compression operation of the heat medium by the compressor until the pressure in the housing space is less than a pressure corresponding to a predetermined concentration of the heat medium contained in the lubricating oil;
4. The compression operation of the heat medium by the compressor is stopped when the pressure is lower than a pressure corresponding to a predetermined concentration of the heat medium contained in the lubricating oil. 5. The heat pump unit according to item 1. A circulation path through which the heat medium circulates;
A compressor having a compression mechanism and a storage space for storing lubricating oil supplied to the compression mechanism, and adiabatically compressing and heating the heat medium circulating in the circulation path;
A condenser that is provided downstream of the compressor in the circulation path and that condenses the heat medium by cooling the heat medium heated by the compressor;
An expansion valve that is provided downstream of the condenser in the circulation path and cools the heat medium condensed by the condenser by decompressing and expanding;
An evaporator provided downstream of the expansion valve in the circulation path and evaporating the heat medium by heating the heat medium cooled by the expansion valve;
A method of operating a heat pump unit comprising
When receiving an instruction to stop the compression operation of the heat medium by the compressor,
The opening of the expansion valve is reduced so that the level of the lubricating oil stored in the storage space does not become less than a threshold value preset in the compressor,
An operation method of a heat pump unit, wherein the expansion valve is fully closed to stop the flow of the heat medium into the compressor through the expansion valve, and then the compression operation of the heat medium by the compressor is stopped .